The present invention relates generally to microwave antennas and, more particularly, to a fast-flared ridged microwave horn antenna which operates over a wide frequency bandwidth and is particularly applicable for use in microwave radar detectors.
Microwave radar detectors are popular automotive accessories, particularly now when speed limits are moving up but still held to 55 and 65 miles per hour, and more powerful, faster cars are having a resurgence in view of reduced oil and gasoline prices. Due to consumer preference for small package size, the most popular radar detectors are approximately 3/4 of an inch in height and 21/2inches in width or less. Such small dimensions are hard to achieve since, as is well known in the art, it is difficult to design a microwave antenna having high directivity over a wide frequency bandwidth if the height of the aperture of the antenna is to be limited. While flared antennas have been used for radar detectors to achieve small package size, high aperture efficiency is difficult to obtain with a large flare angle due to high phase error losses which are incurred in such antennas. Adding to the design difficulties is the recent expansion of the frequency bands which are available for operation of police speed detection radar: such bands now include the X, Ku, K and Ka bands which range from approximately 10 to 35 GHz.
Accordingly, there is a need for a compact microwave antenna for use in state-of-the art microwave radar detectors which can effectively cover the frequency bands now or soon to be employed by police speed detection radars while satisfying consumer demands for small sized radar detectors.